Process of treating lubricating oil stocks



Patented May 24, 1932 UNITED STATES PATENT OFFICE v .TonN 0.1BLAK, or Los ANGELES, wm'r n. 'nIAL, or Los NGELEs COUNTY, AND JOHN R. MCCONNELL, or WHITTIER, CALIFORNIA, ASSIGNORS, BY MESNE ASSIGNMENTS, T0 RICHFIELZD 01L COMPANY or CALIFORNIA, or LOS ANGELES, CALIFORNIA, A

CORPORATION OF DELAWARE PROCESS OF TREATING LUBRIGATING OIL STOCKS No Drawing.

This invention relates to the manufacture of lubricating oil, and while not necessarily thereto, it more specifically refers to the production of a lubricant with a low cold test, derived from an asphalt, a mixed base crude petroleum oil, or a parafline base oil, without the removal or a partial removal of the paraf a crude containing a low paraffine wax content is not obtainable the parafline wax must be removed by an expensive cooling and pressing operation well known in the art.

By this invention these difficulties are overcome and a lubricating oil stock having a lo I cold test may be obtained from a crude 01 containing 0.25% or more parafline wax, by the employment of a solvent for the wax, preferably an oil derived from coal tar, or pitch, by an extraction or distillation operation, and one which has a flash point the same or higher than the lubricating oil stock treated.

. This process is also applicable and desirable for. treating lubricating oil stocks derived from a parafline base crude oil from which the higher melting point wax has been removed by the conventional cooling, filtering and pressing operation. For example, certain lubricating oil stocks derived from a paraffine base crude containing 2% or more paraffine wax may be reducedto 1% of wax, or less, by a cooling and filter pressing opera-' tion at temperatures ranging from 5 to F., but in order to obtain a lubricating stock having a cold test of 15 F., or lower, a second cooling and filter pressing operation is usual-- ly necessary at a temperature of 0 F., or

lower. By this invention the second pressing operation maybe eliminated and a lubricating oil stock obtained having a cold test of 15 F. or lower, by the employment of a solvent of the aromatic series of hydrocarbons,

as heretofore stated.-

Application filed March 28, 1927. SeriaLNo. 177,834.

The addition of this solvent to a lubricating oil stock containing no parafline wax also lowers the cold test and is advantageous from a commercial viewpoint, since it may be used as a blending stock for such lubricating oils that have a higher cold test. It is common commercial practice to mix a lubricating oil stock derived from an asphalt base crude oil having a cold test ofapproximately0 F.,with a lubricating oil stock derived from a parafline base crude having a cold test of approxi-' mately F., to produce a blended stock having acold test of approximately 15 F.

In the application of this invention, coal tar, coal tar pitch of various grades, or, coal tar distillate having a flash the same or higher than the lubricating oil stocks are employed; .also, such stocks may be used to impart a green fluorescence to the oil, which is fully described in the pending application of John C. Black, Wirt D. Rial, and John R.

McConnell, Serial Number 141,424 filed October 13, 1926, to which reference is hereby made.

This process may be carried out by three distinctive methods. 'The oil to which the desired lowering of the cold test is to be effected may be treated directly with the coal tar pitch, which contains extractable high flash aromatic oils, or a concentrated extract may be added directly to the oil, or a high flash aromatic oil' derived from the distillationof coal tar, or coal tar pitch, or other sources of high flash aromatic oils such as may be produced by the destructive distillation of petroleum or shale oils.

As a specific example of a pitch which may be employed, a coal tar pitch made by the distillation of coal tar may be given as an illustration. This pitch may be a reduced residuum resulting from any coal tar distillation in which the low boiling hydrocarbons have been distilled off.-

' In the preferred embodiment of our invention, lubricating oil stock made by any preferred method, with or without an acid treatment, and with'or without the employuntil a uniform fluid mixture is obtained.

This operation is preferably carried out in conjunction withthe well known hot contact decolorizingiprocess, or the hot neutralizing process, or the hot neutralizin and decolorizing process, which employ ely comminuted decolorizing agents of the kaolin division, such as fullers earth, acid treated montmorillonite, and the like, also certain silicates of the serpentine division, such as magnesium silicate; a deposit of which is located near the town of Death Valley, Inyo County, California. This magnesium silicate decolorizing and neutralizing agent has a natural decolorizing efficiency for petroleum oil stocks considerably greater than standard Florida fullers earth.

In the preferred operation of this invention, the lubricating oil stock is charged into a treating tank provided with the means for circulating, agitating, and heating the oil to the desired temperature; approximately 1 by weight of 200 mesh coal tar pitch is then introduced into the oil by means of a conveyor and followed immediately 'or simultaneously by the introduction of the decolorizing agent (200 mesh) using one-fourth to as much as three pounds per gallon of oil charged, depending upon the grade of lubrieating oil stock to be treated. After the introduction of the comminuted coal tar and decolorizing agent the circulating and heating is continued until a uniform mixture is obtained and a temperature of approximately 310 F. is reached. After this temperature hasbeen reached and the extraction and decolorizing reaction is complete, thev treated oil while still hot is separated from the decolorizing agent containing the adsorbed coloring matter and coal tar residue by a filtering operation and then conducted to a storage.

Preferably this treatment with coal tar pitch and a decolorizing agent is carried out on an acid treated lubricating oil stock from which substantially all the sulpho-acids or sludge has been removed,- and without a caustic neutralizingoperation. Also with certain lubricating oil stocks, which may or may not have been given a caustic neutralizing, it is advantageous to add a small percentage of sulphuric acid, a fraction of approximately 1% to 10% by Weight of the neutralizing agent employed, which coagulates or flocculates a part of the coloring matter contained therein, thus rendering such colorin g matter of the lubricating oil stock more readily adsorba'ble by the decolorizing agent during the aforesaid treatment, by means of which alessainount of decolorizing agent is employed to'gbtain the desired grade and color of the lubricating oil stock. The concentration of the sulphuric acid employed is preferably 66 Baum, although other concentrations may be employed, and the acid may be added either before or together with the treating agents. Other flocculating or coagulating agents may be employed instead of the sulphuric acid, such for example as hydrochloric acid gas, anhydrous aluminum sulphate and the like,,'but for commercial reasons we prefer to use sulfuric acid.

In certain lubricating oil stocks having a cold test of 0 F. it was found that a cold test of minus 10 F. was'obtained after being treated by our invention with 1 4% by weight coal tar pitch. I K

' It is to be understood that high flash coal tar distillate may be employed instead of coal tar pitch and that the application of the coal tar pitch or: high flash distillate may be added to the lubricating stock during any stage of the manufacture, providedsuflicient quantities are employed. For example, coal tar pitch, coal tar, or coal tar distillate, may be addeddirectly to the crude oil or, residuum before the distillation operation, or the same may be added to the lubricating oil distillate before or after the acid treating operation.

While the process herein described is well adapted to carry out the objects of the pres ent invention, it is understood that various modifications and changes may be made without departing from the invention, and the invention includes all such modifications and changes as come within the scope of the appended claims.

We claim:

1. A process of lowering the cold test of mineral lubricating oils containing parafiin wax, comprising adding a coal tar pitch containing extractable aromatic compounds and a solid mineral adsorbent to a lubricating oil stock containin paraflin wax, heating and agitatingthe mixture until substantially all of' the extractable aromatic compounds are dissolved by the lubricating oil stock, and then separating the-treated lubricating oil stock containing the extracted aromatic compounds from the solid mineral adsorbent containing the coal tar pitch residue and adsorbed constituents.

2. A process of lowering the cold test of mineral lubricating oils containing parafiin wax, comprising adding a coal tar pitch containing extractable aromatic compounds and a solid mineral adsorbent to a lubricating oil stock containing parafline wax, heating and agitating the mixture until substantially all of the extractable aromatic compounds are dissolved by the lubricating oil stock,- and then separating the treated lubricating oil stock containing the extracted aromatic compounds from the solid mineral adsorbent containing the coal tar pitch residue and adsorbed constituents.

3. A process of lowering the cold test of mineral lubricating oils containing parathn' wax, comprising adding a coal tar pitch containing extractable aromatic compounds and a solid mineral adsorbent to an acid treated wax, comprising adding a coal tar pitch containing extractable high flash aromatic compounds and a solid mineral adsorbent to an acid treated lubricating oil stock containing parafiine wax, heating and agitating the mixture until substantially all of the extractable high flash aromatic compounds are dissolved by the lubricating oil stock and then separating the treated lubricating oil stock containing the extracted aromatic compounds from the solid mineral adsorbent containing the coal tar pitch residueand adsorbed constituents.

In testimony whereof we aflix our signatures.

JOHN C. BLACK. WIRT D. RIAL. JOHN R. MOCONNELL. 

